This application claims the priority of German patent document 103 55 221.9, filed Nov. 26, 2003, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a method and apparatus, including a computer program, for determining when the driver of a vehicle (in particular a motor vehicle) is not paying attention during operation of the vehicle. The invention also relates to a computer readable storage medium encoded with such a computer program.
Various proposals have been made for detecting inattentiveness of a motor vehicle driver, including in particular a tendency for the motor vehicle driver to go to sleep. For example, German patent document DE 198 18 239 A1 discloses for this purpose an apparatus that comprises firstly a vehicle environment identification device for detection of the actual driving style of the motor vehicle driver, as well as a device for detecting a reference driving style (in particular, how many lateral self-movements there normally are by the motor vehicle driver in his driving style). Finally, the disclosed apparatus has comparison logic for comparing the reference driving style with the current actual driving style in order to output a warning to the motor vehicle driver based on the result of this comparison.
Furthermore, U.S. Pat. No. 6,061,610 discloses a method and apparatus for determining stress of the driver of a motor vehicle by detecting the steering wheel angle of the motor vehicle first of all in order to generate prediction errors for the steering wheel angle in the driver's control of the motor vehicle. A distribution of these prediction errors is then calculated and compared with another distribution of prediction errors of the steering wheel angle which represents a predetermined steering behavior of a stress-free or unstressed driver rather than the real steering behavior of the driver. The result of this comparison then represents the current stress on the driver while driving the motor vehicle.
German patent document DE 25 46 345 discloses a driver warning device for warning motor vehicle drivers before they go to sleep. The device detects the steering movement of the driver of the motor vehicle, on the assumption that, when the driver is awake, the steering wheel is not held entirely quiescent, even when traveling in a straight line; rather, steering movements are also still carried out continuously, even if they are very small. If the driver warning device detects absence of such steering movements over an adjustable time interval, as well, then the driver warning device deduces that the driver is going to sleep or is at least at risk of going to sleep, and warns him or her by outputting a signal.
The driver warning device disclosed in the German patent document DE 25 46 345 has the disadvantage that the decision on when the driver of a vehicle is not paying attention is made solely on the basis of the detection of a steering quiescent phase; thus, this decision can be made only vaguely and unreliably.
Japanese patent document JP 07-093678 A describes an apparatus for identification of fatigue by identification of a steering quiescent phase with subsequent identification of a corrective steering action.
Against the background of this prior art, one object of the present invention is to provide a method and apparatus (including a corresponding computer program) to identify when the driver of a motor vehicle is not paying attention, as well as a controller for carrying out this method and a data storage medium encoded with such a computer program, which make it possible to identify more reliably identify possible inattentiveness of the driver.
This and other objects and advantages are achieved by the method according to the invention, which includes the following steps: identification of a steering action following a steering quiescent phase; determination of the magnitude of the extent of this steering action by evaluation of the rate of change of the steering wheel angle; and determination of a measure of the severity of the inattentiveness by the driver by assessment of the result of a link between the extent of the steering quiescent phase and the extent of the steering action.
In the process of identification of inattentiveness of the driver, the invention advantageously distinguishes between a steering quiescent phase and a more or less hectic steering action which typically follows a state of inattentiveness. Thus, according to the invention, a state of inattentiveness is not assumed unless both the steering quiescent phase and the subsequent steering action are identified in conjunction with one another. Conversely, this means that identification of a steering quiescent phase or of a steering action by itself is not sufficient to deduce inattentiveness of the driver. The detected extents of both the quiescent phase and of the steering action are logically linked to one another for determination of the extent of the severity of the inattentiveness, and the result is then assessed.
In modern vehicles, in particular motor vehicles, a sensor for detection of the steering wheel angle x is normally provided in any case. Thus, in principle, no additional sensors are advantageously required to implement the described method.
Two different representative embodiments for implementation of the invention will be explained in the description. In principle, a specific way to determine the extent of the steering quiescent phase is provided in the second exemplary embodiment; however, this determination process can also be carried out according to the first exemplary embodiment.